1. Field of the Invention
The present invention relates to the technical field of liquid crystal displaying, and in particular to a backlight module that provides excellent thermal conductivity.
2. The Related Arts
Liquid crystal display (LCD) has a variety of advantages, such as compact device size, low power consumption, and being free of radiation, and is thus widely used. Most of the LCDs that are currently available in the market are backlighting LCDs, which comprise a liquid crystal panel and a backlight module. The working principle of the liquid crystal panel is that liquid crystal molecules interposed between two parallel glass plates and a plurality of vertical and horizontal fine electrical wires is arranged between the two glass plates, whereby the liquid crystal molecules are controlled to change direction by application of electricity to refract light emitting from the backlight module for generating images. Since the liquid crystal panel itself does not emit light, light must be provided by the backlight module in order to generate images. Thus, the backlight module is one of the key components of an LCD. The backlight module can be classified as two types, namely side-edge backlight module and direct backlight module, according to the position where light gets incident. The direct backlight module arranges a light source, such as a cold cathode fluorescent lamp (CCFL) or a light-emitting diode (LED) at the back side of the liquid crystal panel to form a planar light source to directly provide lighting to the liquid crystal panel. The side-edge backlight module arranged an LED light bar at an edge of a backboard that is located rearward of one side of the liquid crystal panel. The LED light bar emits light that enters a light guide plate through a light incident face of the light guide plate and is projected out through a light exit face after being reflected and diffused to thereby form a planar light source to be provided to the liquid crystal panel.
The conventional arrangements of heat dissipation for the LED backlight module often fix the light bar on a bracket and mount the bracket to the backboard. Fastening is often done with bolt or heat dissipative adhesive tapes, of which the former may easily cause air thermal resistance between the light bar and the bracket, leading to reduced heat dissipation performance, while the later has low coefficient of thermal conductivity, which severely affects the performance of heat dissipation. Further, the light bar shows relatively high temperature at a middle portion and relatively low temperatures at two opposite end portions during the operation thereof, and thus, special processing must be taken for the bracket in order to ensure the whole bracket shows temperature balance and to prevent occurrence of abnormal displaying of image due to localized excessive high temperature. However, this surely brings a consequence of increasing processing cost.
To handle such a problem, Chinese Patent No. 201120142696.3 discloses an LED backlight source and a liquid crystal panel (as shown in FIG. 1). The LED backlight source comprise a backboard 1, heat conduction blocks 2 mounted to the backboard 1, and LED light bars 3 mounted on the heat conduction blocks 2. The LED backlight source also comprises a heat pipe 3. The heat pipe 3 has a high temperature end that is set in contact with the heat conduction block 2. A low temperature end of the heat pipe 3 is set at a location distant from the LED light bars 4 and is in contact with the backboard 1. As such, the temperature is made uniform through the whole backboard and the life span of the LED light bars is extended. However, such a technical solution increases the cost of the LED backlight module to quite an extent and the number of structural components is great, making the assembling tedious and defect rate of assembling increased.